Indian Railways making use of drones for planning the laying of rail tracks.
The objective was to do plan and lay a new rail line parallel to the existing rail line from Amethi to Janghai in Uttar Pradesh.
Terms Used
- Doubling: The process of laying of a new railway line parallel to the existing one is called as doubling. It is done to allow trains from both the directions can run simultaneously.
- Alignment: The horizontal and vertical layout including the direction of the railway line.
- Total Station: It is an electronic instrument used for measuring precise distances and slope from one point to another. It is commonly used in surveying.
- DGPS: It refers to Differential GPS or Differential Global Positioning System. DGPS is usually more accurate than the normal GPS. The accuracy of DGPS is in the range of ~1cm while that of GPS is 5m to 15m.
- Orthomosaic: 2D map created by stitching multiple images using photogrammetry technique.
Background
According to a news report, Indian Railways has set an ambitious target of big rail projects for 2019, that includes timely commissioning new lines, gauge conversion and doubling projects. One of them include doubling of Amethi to Janghai section, in Uttar Pradesh.
Besides, for any doubling project, one of the major task is to do a final location survey in order to finalise the alignment of the proposed rail line. Earlier, this survey was most commonly done using DGPS or/and Total Station. Using this technique, Total Station is used to mark left and right sides of the existing rails. Then, these points are exported to CAD, and the rail line is marked by joining those points.
However, with the rise of new technology such as drones and digital photogrammetry, the surveying technique has improved a lot.
Now, drones are used to do planning and monitoring of the construction and maintenance projects.
Problems/Challenges
- Traditional surveying (using Total Station and DGPS) needs a lot of man hours both in the field as well as in the office.
- Too much field work is required for the survey of even a smaller section (~ 200 km).
- Since all the working plans(CAD plans) are developed using single instrument, there is no method to check the reliability and accuracy of obtained data.
- Often, many rails are missed near the railway yards where a lot of tracks merge together.
To solve the above challenges and make things efficient, Indian Railways has adopted the use of drones and digital photogrammetry.
Methodology Used
We used our UAV(Kepler, mounted with GPS) to fly over the Amethi to Janghai railway track and captured number of high-resolution images. Then we used photogrammetry techniques to stitch those images and create a 2D map and elevation model of the entire section. We also captured aerial videos to get the overview of the section.
Solutions
Let us look at how drones prove to be much more beneficial in conducting the final location survey for the doubling of Amethi-Janghai section in Northern Railways.
- Overview of Topography and Land Cover: First of all, aerial videography is done using drones that help in getting a quick overview of the topography and land cover of the entire section.
- Drone Survey of the alignment: Drone is used to carry out aerial survey of the alignment and create a 2D map of the entire section, also called as orthomosaic. Then, we generated digital terrain model of the entire section, and did all the measurements and planning on the map itself.
- CAD Plan: All the working CAD plans are made on top of orthomosaic. This completely eliminated the need of regular field visits. CAD plan includes Tracks, Stations, Curves, Buildings, LC etc. including their chainages.
- Yard Plan: Orthomosaic is also used to create detailed yard plan of Pratapgarh station for platform expansion planning, track management, asset management.
Orthomosaic serves as the base data which serves multiple purpose.
Note: Orthomosaic can also be used in Autodesk, Bentley, ArcGIS design softwares.
Advantages
- Fast: A 200km section can be surveyed within a week.
- Minimal human efforts required: Not more than 2 or 3 people are required for even upto 2000km.
- Reliable: Accuracy of the data can always be verified using orthomosaic in case of any uncertainty. Plus, nothing can be missed in producing the CAD plans, if created on top of orthomosaic.
- Terrain-independent: Drones are terrain-independent as it fly in the open air. Hence, no additional efforts are required because of a hilly region or rivers or bridges. However, land-based methods are terrain-restricted and, thus, it need extra efforts and supervision based on the topography.
- Identifying obstacles: The land boundary can be superimposed on orthomosaic, thus making it extremely helpful in identifying issues of land acquisition or clashes with the existing construction projects.
- Efficient collaboration: All the concerned members in the project can visualise the drone-based digital data anytime, anywhere. This enables better planning and decision-making.
Technical Information
Section length: 87 km
ROW covered: 120 meters
Ground Sampling Distance: 5cm
No. of images captured and merged: 5167 images
Image overlap: 80% Frontal, 80% Sideways
No. of structures/features: 98 bridges, 41 level crossings
About Indshine
Indshine provides geospatial insights and design solutions for Highways, Railways, Mining, Forestry, and Power Transmission. We also creates digital maps and 3D models by capturing data through drones, satellites and Lidars. These are widely used in smart city planning, surveying of a given site, monitoring the site progress, and inspecting various kinds of structures such as bridges, dams, pipelines, high walls, etc.
Moreover, based on the industry’s requirements, we have developed a project collaboration platform called Felix (felix.indshine.com) which allows all the stakeholders to visualise the area of interest, generate spatial insights, discuss with other members, and make informed decisions quickly.
For more information, kindly send us an email at info@indshine.com or visit www.indshine.com.
